Hi Andrii,
Some nits inline, nothing blocking though.
2019-05-23 13:42 UTC-0700 ~ Andrii Nakryiko <andriin@xxxxxx>
> Utilize new libbpf's btf_dump API to emit BTF as a C definitions.
>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
> tools/bpf/bpftool/btf.c | 74 +++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 72 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> index a22ef6587ebe..1cdbfad42b38 100644
> --- a/tools/bpf/bpftool/btf.c
> +++ b/tools/bpf/bpftool/btf.c
> @@ -340,11 +340,48 @@ static int dump_btf_raw(const struct btf *btf,
> return 0;
> }
>
> +static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
Nit: This function could have a printf attribute ("__printf(2, 0)").
> +{
> + vfprintf(stdout, fmt, args);
> +}
> +
> +static int dump_btf_c(const struct btf *btf,
> + __u32 *root_type_ids, int root_type_cnt)
> +{
> + struct btf_dump *d;
> + int err = 0, i;
> +
> + d = btf_dump__new(btf, NULL, NULL, btf_dump_printf);
> + if (IS_ERR(d))
> + return PTR_ERR(d);
> +
> + if (root_type_cnt) {
> + for (i = 0; i < root_type_cnt; i++) {
> + err = btf_dump__dump_type(d, root_type_ids[i]);
> + if (err)
> + goto done;
> + }
> + } else {
> + int cnt = btf__get_nr_types(btf);
> +
> + for (i = 1; i <= cnt; i++) {
> + err = btf_dump__dump_type(d, i);
> + if (err)
> + goto done;
> + }
> + }
> +
> +done:
> + btf_dump__free(d);
> + return err;
> +}
> +
> static int do_dump(int argc, char **argv)
> {
> struct btf *btf = NULL;
> __u32 root_type_ids[2];
> int root_type_cnt = 0;
> + bool dump_c = false;
> __u32 btf_id = -1;
> const char *src;
> int fd = -1;
> @@ -431,6 +468,29 @@ static int do_dump(int argc, char **argv)
> goto done;
> }
>
> + while (argc) {
> + if (is_prefix(*argv, "format")) {
> + NEXT_ARG();
> + if (argc < 1) {
> + p_err("expecting value for 'format' option\n");
> + goto done;
> + }
> + if (strcmp(*argv, "c") == 0) {
> + dump_c = true;
> + } else if (strcmp(*argv, "raw") == 0) {
Do you think we could use is_prefix() instead of strcmp() here?
> + dump_c = false;
> + } else {
> + p_err("unrecognized format specifier: '%s'",
> + *argv);
Would it be worth reminding the user about the valid specifiers in that
message? (But then we already have it in do_help(), so maybe not.)
> + goto done;
> + }
> + NEXT_ARG();
> + } else {
> + p_err("unrecognized option: '%s'", *argv);
> + goto done;
> + }
> + }
> +
> if (!btf) {
> err = btf__get_from_id(btf_id, &btf);
> if (err) {
> @@ -444,7 +504,16 @@ static int do_dump(int argc, char **argv)
> }
> }
>
> - dump_btf_raw(btf, root_type_ids, root_type_cnt);
> + if (dump_c) {
> + if (json_output) {
> + p_err("JSON output for C-syntax dump is not supported");
> + err = -ENOTSUP;
> + goto done;
> + }
> + err = dump_btf_c(btf, root_type_ids, root_type_cnt);
> + } else {
> + err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
> + }
>
> done:
> close(fd);
> @@ -460,10 +529,11 @@ static int do_help(int argc, char **argv)
> }
>
> fprintf(stderr,
> - "Usage: %s btf dump BTF_SRC\n"
> + "Usage: %s btf dump BTF_SRC [format FORMAT]\n"
> " %s btf help\n"
> "\n"
> " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
> + " FORMAT := { raw | c }\n"
> " " HELP_SPEC_MAP "\n"
> " " HELP_SPEC_PROGRAM "\n"
> " " HELP_SPEC_OPTIONS "\n"
>
